78 votes

Why do some bad traits evolve, and good ones don't?

During the process of selection, individuals having disadvantageous traits are weeded out. If the selection pressure isn't strong enough then mildly disadvantageous traits will continue to persist in ...
39 votes
Accepted

Are there animals that have evolved a resistance to human activity or encroachment?

Note: This is an answer to the last line of your question. A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth. Here is a brief ...
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37 votes

Why do some bad traits evolve, and good ones don't?

There's always the most obvious: Evolution is chance. Some traits allow an individual to have a higher chance to produce offspring. That doesn't mean individuals with that trait have more offspring, ...
36 votes
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Why does my room suddenly look 'reddish'? My eyes seem to adapt to color

Short answer The phenomenon you describe can be explained by the negative afterimage effect, which indeed is elicited by adaptive processes in the retinae. Background In the retina there are three ...
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25 votes

Are there animals that have evolved a resistance to human activity or encroachment?

Many insects (as well as some other animals) have documented resistance to pesticides. For example, the German cockroach (Blattella germanica) can be resistant to multiple insecticides1. In addition, ...
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23 votes

Why do some bad traits evolve, and good ones don't?

Because evolution is an effect, not a cause. That is, there's no "God of Evolution" out there deciding that this or that trait would be beneficial to a species, and deciding to add it. Evolution ...
18 votes

Are there animals that have evolved a resistance to human activity or encroachment?

Bighorn sheep are developing smaller horns and elephants are becoming tuskless in Africa: The horns of some bighorn sheep are getting smaller, because hunters are picking off the most impressive ...
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16 votes
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Why is green fur not a thing?

The technical answer is: Because the coloration of skin and hair is done by the two forms of melanin: Eumelanin, which is dark brown to black and Pheomelanin which is yellow to red. This enables ...
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16 votes

Why do some bad traits evolve, and good ones don't?

Below are the reasons I can think of. The list is not exhaustive and there are some conceptual overlaps. The trait seems advantageous but it is not, maybe due to its effect on another component of ...
14 votes
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Why aren't there any transitional animals today?

Every species on the planet is "transitional" - this is because there is no ultimate or final species. Species branch out from one another, sometimes species go extinct, leaving gaps between the ...
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14 votes
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Why do humans grow taller than their ancestors?

A likely misunderstanding of yours Now we almost don't fight with other species Misunderstanding about selection As you will go through this course, you will understand why this sentence makes ...
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12 votes

Why do some bad traits evolve, and good ones don't?

Evolution occurs by a change in gene frequencies, with gene frequencies potentially affected by four mechanisms (mutation, migration, drift, and selection). The answer to the question Why does the ...
9 votes

Why is green fur not a thing?

Just to add a different dimension to the answer from @Chris. Not all animal colouration is produced by melanin. A whole range of bright colours in insects, birds and reptiles comes under the heading ...
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9 votes
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Why do rabbits often have white hindquarters?

Apparently the most noticeable research on this subject of a rabbit's white behind has been done by Dr Dirk Semmann of the University of Goettingen. He proposes that these spots actually confuse ...
9 votes

What exactly does adaptive mean?

The question is probably more complicated than it seems because, if I am not wrong, the word adaptation here is understood at the group level. Definitions of adaptation Unfortunately, there is not ...
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9 votes

Do Traits Have to be Adaptive in Order to Survive?

Good question. And good analysis. I have little to add! I'll simply provide my own list of thoughts to complement your ideas, which are not mutually exclusive. The fact that it wasn't discarded ...
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8 votes

Empirical evidence for Group Selection?

Let's start with your definition. "Selection for traits that would be beneficial to a population of units at the expense of an individual unit possessing the trait" This is not a good definition of ...
8 votes

Why do some bad traits evolve, and good ones don't?

All the previous answers are very good. However, I feel a point was missed (or maybe I didn't read deeply enough). I will highlight the concept of fitness landscapes. This is how it looks: The peaks ...
7 votes
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What exactly does adaptive mean?

A trait is said to be adaptive when it causes fitness to increase. Fitness is generally understood as the (relative) contribution to future generations in terms of offspring or genes. The trait is ...
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7 votes
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Is addiction adaptive?

Albeit used in the keywords of the paper, feather pecking is not an addiction, but normal behavior turned pathological in artificial (overcrowded) environments. Addiction typically arises through ...
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7 votes

Why aren't there any transitional animals today?

This is just going to be a quick answer, as it's too long for a comment (I'll leave it to others to fill in the gaps if they wish). The image you present in your question is based on a false premise. ...
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7 votes
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What kind of owl does this moth look like?

First of all what a nice foto! I think this is Antheraea polyphemus. According to Wikipedia, the moth has an average of 15 cm (6 in). The purplish eyespots on hind wings give its name - from the ...
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6 votes
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Cross-integration of puma subspecies populations

The study you are referring to is probably a study by Culver et al. (2000). They performed a genetic analysis of 315 individuals of the American Puma (Puma concolor), also known as the cougar. Their ...
6 votes

Why is green fur not a thing?

A dimension not explored by the other (excellent) answers has to do with color perception under trees. Leaves are green while on the tree, which tends to make mostly green light available to the ...
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6 votes
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Can the apparent drop in insect population be explained by local insects evolving to avoid traps?

From your own PlosOne link comes proof that the selection pressure was very weak: "Most locations (59%, n = 37) were sampled in only one year, 20 locations in two years, five locations in three years, ...
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5 votes
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Is Batesian mimicry more important for females?

In sexually dimorphic ant-mimicking spiders, it depends on the specific species which sex resembles the ant most (Cushing, 2012). In many cases of sexually dimorphic spider myrmecomorphs, the male is ...
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5 votes

What exactly does adaptive mean?

Your questions mean basically the same. Birdcare.com says: The situation in which all the eggs in a clutch do not hatch at (more or less) the same time, as is more usual among birds, but have ...
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5 votes

Why do some bad traits evolve, and good ones don't?

Richard Dawkins devoted an entire chapter of The Extended Phenotype to this question, Constraints on Perfection (the third chapter in the edition I have to hand); he listed six (not including those he ...
5 votes

Do any terrestrial herbivores use auditory crypsis for predator avoidance?

Does soundproofing count? Most predators locate prey using visual or olfactory cues; the only predators I can think of that use auditory cues are nocturnal ones - owls and bats. Bats, of course, use ...
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5 votes

Why do humans grow taller than their ancestors?

In my opinion there is a fallacy in your understanding of evolution. First of all evolution is blind to the future. Also living organisms don't undergo evolutionary changes toward something that might ...
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